Re: [PATCH 2/3] perf/core: introduce pmu_event_flags and PMUEF_READ_CPU_PKG

Peter Zijlstra
2016-08-04T15:00:58Z

On Mon, Aug 01, 2016 at 07:44:54PM -0700, David Carrillo-Cisneros wrote:
> Introduce the flag PMUEF_READ_CPU_PKG, useful for uncore events, that
> allows a PMU to signal the generic perf code that an event is readable
> on the current CPU if the event is:
> - active in a CPU in the same package as the current CPU (local CPU)

Ok that I get..

> - not active but is attached to a CPU (i.e. event->cpu != -1) in the
> same package as the current CPU.

but this, not so much. Why would you want to read an inactive counter?